To provide steering assistance in accordance with the turning operation on a steering wheel, conventional steering assist control techniques controlling assist torque have been used in vehicles.
One type of steering assist control technique disclosed in Patent Literature 1 uses multiple actuator units to control the assist torque. When an anomaly occurs in one of the actuator units, this type of technique stops the anomalous actuator unit. In the event of such a one-unit anomaly, a remaining normal actuator unit continues to output torque and thereby maintains the steering assisting function. This provides enhanced failsafe capability.